Safety device for presses.



R. vB. BENJAMINL SAFETY DEVICE Fon PRESSYES. APPLICATION FILED APR. 25,19l3.

Patented 0 013. 9, 1917.

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R. B. BENJAMIN.

SAFETY DEVICE FOR PRESSES.

APPLlCATION FILED APR. 25. 1913.

1,242,642., Patented Oct. 9,1917.

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49 jwezzzzr UED STATES PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO, ILLINOIS, ASSIGNOR TO BENJAMIN ELECTRIC MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SAFETY DEVICE FOR PRESSES.

Specification of Letters Patent.

Application filed April 25, 1913. Serial No. 763,576.

17 all whom it may concern:

. had to the accompanying drawing,'forming a part of this specification.

My invention relates to improvements n safety manipulating devices for ntermittently operated machinery, and particularly to devices for intermittently operating punch presses and the like.

One of the objects of my invention is to provide an operating mechanism for tripping devices of punch presses which while permitting the utmost freedom in the movement of the hands of the operator in feeding the Work to and removing the work from the press, will insure the hands of the operator being outside the zone of danger of the press before the press is tripped, and which will prevent the tripping of the press as long as either or both of the hands of the operator are in a dangerous position.

Another object of my invention is to provide a safety mechanism of the above character which requires no attention on the part of the operator, which does away with the manipulation of levers, etc., on the part of the operator, and merely requires that the hands of the operator be brought to a (position of safety before the press is trippe For the purpose of disclosing my invention I have illustrated in the accompanying drawings one form thereof applied to a punch press, in which drawings- Figure l is a side elevation of a punch press with my invention applied thereto;

Fig. 2 is a front elevation thereof;

Fig. 3 is a sectional view of one of the controlling switches taken on the line 33 of Fig. 4;

Fig. 4 is a sectional view thereof taken on the line 4-l of Fig. 3;

Fig. 5 is a detail of the connection between one of the controlling rods and its controlling switch; and

Fig. 6 is a diagrammatic view of the controlling circuit.

Referring to the structure illustrated in the drawings, the machine 1 is a punch press of the kind which is adapted to run open if desired. This press has the usual frame Qrand a tripping mechanism 3 by means of which the clutch between the punch and the source of power is thrown into driving connection. The tripping mechanism may be of any of the well known constructions and a description of it is not therefore required here, except to state that after the clutch has been thrown and has caused the punch to descend it is automatically disconnected and will not cause the punch to descend a second time until the tripping mechanism is thrown. This tripping mechanism is operated by an operating solenoid 4 which is connected to the movable member of the tripping mechanism by a suitable cnnecting rod 5.,

The circuit through the solenoid 4 is con trolled by a switch 6 which when the solenoid operates to trip the press is opened, thereby opening the circuit of the solenoid 4; and by suitable hand-controlled switches 7 and 8, the operation and purposeof which will be more fully hereinafter described. The switch 6 is reset by a switch-closing solenoid 9, the circuit of which is also controlled by the hand-operated switches 7 and 8, and this switch 6 is held in an open or closed position by means of the latch 10. The front end of the switch 6 bears upon a roller 11 of the latch 10, which latch is pivoted at 12 and is forced against the front end of the switch by a coiled spring 13.

When the switch is forced downward by the downward movement of the lower end of the core of the solenoid in tripping the press,

it will snap past the roller 11 and be held.

in its lower or open position until it is moved to a closed position by the solenoid 9. When it is moved to the closed position by the solenoid 9, it will snap up past the roller 11 and be held in its closed position even though the circuit through the solenoid 9 be open.

The hand-operated controlling switches 7 and 8 are mounted preferably on the front part of the press on the top thereof, and as the switches are exactly alike in construction a description of only one will be necessary. The switch 7 comprises an inclosing casing 14 within which the various electrical parts are adapted to be inclosed. This casing is supported upon a bearing 15 which extends into the casing and is secured to a portion 16 of the frame of the but the electrical connection may be made therewith by conductor wires. A similar pair of contacts 21 and 22 is located at the bottom of the disk. These contacts are adapted to be bridged by a suitable contact arm 23 provided with brushes 24 and 25 adapted to engage respectively the contacts 18 and 19 and the contacts 21 and 22. The arm 23 is clamped between a pair of insulating arms 26, which in turn are mounted upon a rotatable shaft 27- supported in journal 15. The rear end of this shaft which projects through the portion 16 of the frame, is provided with a screw-threaded extension 28 and has suitable washers 29 and 30 thereon. The washer 29 bears against the frame 16, and the washer 3O bears against a nut 31 on the screw-threaded end of the shaft 27. Between these two washers is interposed a coiled spring 32 by which the brushes 24 and 25 may be held in suitable tension engagement with the contacts on the disk. The front end of the shaft 27 which extends beyond the front cover 33 of the casing, is provided with a bifurcated arm 34 between the bifurcations of which is pivoted a hollow block 35. Extending through this hollow block is an operating arm 36 held in suspension by a coiled spring 37 interposed between a suitable adjustable collar 38 on the arm 36 and the lower portion of a stirrup 39. The upper ends of this stirrup are suitably supported by the pivots of the block 35. This arm 36 extends downward to a point immediately above the table 40 of the press and is provided at its lower end with a strap 41 by which it is connected to the right hand of the operator. This strap preferably takes the form illustrated in the drawings, whereby it may be readily passed around the hand of the operator back of the fingers, and will, while permitting perfect freedom of movement of the fingers and hand of the operator, cause the arm 36 to move w th the hand of the operator. Due to its particular form and mounting, this arm may be moved in any direction, but it will be noted that it is only during its back and forth movement that the arm causes the rotation of the shaft 27 and thereby causes the arm 23 of the. switch to move.

The switch 8, as before stated, is of similar construction to the switch first described, being provided with contacts 42 and 43 at its upper portion and contacts 44 and 45 at its lower portion. The contacts 44 and 45 are bridged by a metal jumper 46. This switch is likewise provided with an operating arm 47 of a construction simi-. lar to the arm 36 and having at its lower end a strap or other suitable means for connecting it to the left hand of the operator.

The circuit arrangement of the controlling switches and solenoids. is disclosed in Fig. 6 of the drawing. In this figure it will be seen that one terminal of the tripping solenoid 4 is connected by the conductors 48 and 49 with one terminal of a suitable source of power. The opposite terminal of the solenoid 4 is connected with a contact 50 of the switch 6. A second contact 51 of this switch is connected by the conductor 52 with the contact 21 of the switch 7. The contact 22 of this switch 7 is connected by the conductor 53 with the opposite terminal of the source of power.

One terminal of the setting magnet 9 is connected by the conductors 54 and 49 with one terminal of the source of power, and the opposite terminal of this magnet is connected by the conductor 55 with the contact 43 on the switch 8, and by the conductors 55 and 56 with the contact 19 on the switch 7. The contacts 18 and 42 of the switches 7 and 8 are connected by the conductor 57, and the contact 45 of the switch 8 is connected by the conductor 58 with the conductor 53. It will thus be noted that the circuit through the solenoid 4 can never be completed except when the switch 6 is closed and when the contacts 18 and 21 of the hand-operated switch 7 and the contacts 42 and 45 of the switch 8 are closed, it being observed that these switches for the purpose of closing the circuit through the solenoid are in series. The circuit can only be closed through the contacts 18 and 21 and 42 and 45 of the two switches 7 and 8 when the lower ends of the operating arms 36 and 47 are in a position beyond the zone of danger of the operating mechanism of the press, to insure the operators hands being out of danger. While the circuit through the solenoid 4 can only be closed with the hands of the operator in the above mentioned position, the circuit through the switch-closing magnet 9 will be closed when either one of the hands of the operator is moved to a forward position or to a position for the purpose of inserting work in the machine or removing work therefrom; that is, when either one of the sets' of contacts 19 and 22 of the switch 7 and 43 and 44 of the switch 8- are bridged, and these sets of contacts are bridged by the forward movement of the hand and with it the respective controlling arms when the hand is moved to a position to insert work in the press or remove work therefrom.

In operation, we will assume that the parts are in the position illustrated in the drawings. With the parts in this position the pulley of the press is running free and the controlling switch 6 is open. As soon as the operator picks up a piece of work and moves either one of his hands forward (we will assume that he moves his right hand) to insert the work in the press, the lower end of the arm'36 is moved forward, thereby bridging the contacts 19 and 22, and the circuit will therefore be completed through the magnet 9 as follows: from the source of power by conductor 53 to contact 22, across the bridging arm of the switch 7 to contact 19, theqce by way of conductors 56 and 55 through the solenoid 9, and by conductors 54 and 49 to the opposite side of the circuit. The circuit through the switchclosing magnet 9 being thus closed, the magnet will immediately close the switch 6 and the circuit of the magnet may be closed as soon as the operator withdraws both of his hands from the zone of danger of the mechanism of the press. As soon as the operator withdraws his right hand out of the zone of danger, assuming that the left hand isv already out, the switch arm of the switch 7 will be thrown in an opposite direction, thereby closing the circuit through contacts 18 and 21, and the operators left hand hav-' ing already been withdrawn, circuit will be closed through the contacts 42 and 45; therefore the circuit through the magnet 4 will be as follows: from the plus side of the circuit by way of conductors 53 and 58 "to contact 45, thence across the bridging arm of the switch 8 to contact 42 of this switch, thence by way of conductor 57 to contact 18 of the switch 7, across the bridging arm of this switch to contact 21, thence by conductor 52 across the switch 6 to the magnet 4, through the magnet 4 and by conductors 48 and 49 to the opposite side of the line. The circuit through the solenoid 4 thus being closed, the solenoid will draw down its core and with it the rod 5, thereby tripping the press and causing its punch to descend. As soon, however, as the magnet 4 draws down its core a projection on the lower end of its core strikes the switch' 6, knocking the same open so that the circuit of the magnet 4 cannot be closed until this switch has thereby been reset. But no movement of the hands in picking up the work or moving over the table of the press will effect a tripping of the press until either one of the hands has been moved sufficiently far forward to place the work in the press, thereby closing the circuit through the magnet 9, which Wlll throw the switch 6 and place the circuit of the solenoid 4 in condition to be closed again by the withdrawal of the hands from the zone of danger.

It will be seen from the above that while the work of the operator is not in any way interfered with during the feeding of the work to the press or removing the work therefrom, the hands of the operator must be in a position of safety before the press can be tripped. It will also be seen that it requires no attention on the part of the operator to attend to the tripping of the press; he merely moves his hands in the ordinary sequence of operation, withdrawing them each time out of the zone of danger, and that this ordinary sequence of operations on the part of the hands of the operator automatically causes the tripping mechanism to be set in motion. The safety device, therefore, not only provides means for insuring safety to the operator, but facilitates his work by relieving him of the necessity of thinking about keeping his hands out of a dangerous position.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of power means for operating the movable member, a pair of interlocked controlling devices connected to and movable with the hands of the operator for controlling said power means and arranged to cause said operating means to move said movable member only when both hands of the operator are outside the danger zone of the press.

2. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of a .mo-

tor, means for rendering said motor inoperative when it has moved the movable member to trip the press, a pair of controlling devicesfor said motor, a pair of arms for said controlling devices movable with the hands of the operator, said controlling devices being adapted to individually render said motor operative when the hands are moved toward the mechanism of the press, and arranged to cause said motor to operate when collectively operated and only when the hands of the operator are outside the danger zone of the press.

3. In a device of the character described, the combination with a movable member for lid tripping the clutch of a press, of an electromagnetic motor, a switch in the circuit of said motor arranged to be opened by the motor when it moves the movable member to trip the clutch, a pair of arms movable with the hands of the operator controlling the circuit through said motor and controlling the resetting of said switch, said arms being arranged to cause the resetting of said switch when either is moved with the hand of the operator toward the operating mechanism of the press, and arranged to cause said motor to operate only when both hands of the operator are outside the danger zone of the press.

4. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of means for operating said movable member, means for rendering said means inoperative as soon as the movable member has been moved to trip the clutch, controlling means movable with the hands of the operator arranged to render said operating means operable when either hand is moved toward the mechanism of the press, and arranged to cause said operating mechanism to operate only when both hands of the operator are outside the danger zone of the press.

5. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of an electromagnet for operating said movable memher, a switch in the circuit of said electromagnet arranged to be opened when said electromagnet operates said movable member, means for resetting said switch, a pair of switches arranged in series for controllin the circuit through said electromagnet, an a pair of arms connected with said switches and movable with the hands of the operator, said arms being arranged to individually cause the resetting of said switch when either of the hands of the operator is moved toward the mechanism of the press, said arms being arranged to cause said switches to close the circuit through said electromagnet only when both hands of the operator are outside the danger zone of the press.

6. In a device of the character described, the combination with a movable member for tripping the clutch of a press, of an electromagnet for operating said movable member, a switch in the circuit of said electromagnet arranged to be opened when said magnet o erates the movable member to trip t e clutch, an electromagnet for resetting said switch, a pair of switches each switch having two sets of contacts, one set of contacts being arranged to control the circuit through the operating electromagnet and the other set of contacts being arranged to close the circuit through the resetting magnet, the

neeaece contacts of the two switches controlling the circuit through the operating magnet being arranged in series and the contacts of the two switches controlling the circuit through the resetting magnet being arranged in multiple, a pair of arms for operating said switches said arms being movable with the hands of the operator and arranged to operate said switches to close the circuit through said resetting magnet when either hand of the operator is moved toward the mechanism of the press, and said arms being arranged to operate said switches to close the circuit through said operating magnet only when both hands of the operator are outside the danger zone of the press.

7. In a device of the character described, the combination with a movable member for tripping the clutch of the press, of a solenoid for operating said movable member a switch in the circuit ofi said solenoid 35 opened by the operation of the solenoid means for resetting said switch controlled by either of two members movable with the operators hand, and a second switch in the solenoid circuit controlled by said members and arranged to be closed when both hands of the operator are out of the zone of danger.

-8. In a device of the character described, the combination with a movable member for tripping the clutch of the press, of a solenoid for operating said movable member, a switch for controllin the circuit of said solenoid, means for closing said switch, hand manipulated devices operatin said means, said means being inoperative d closing the circuit of the solenoid when the hand manipulated devices are individually operated, and operative for closing the circuit of the solenoid when the hand manipulated devices are operated collectively and when both hands of the operator are out of the zone of danger.

9. The combination with a hand feed machine having a part movable in a definite path, for operating on material, of means whereby the movement of the hand of the operator to a position adjacent the path of said part will prevent movement of said part, and whereby movement of the hand of the operator to a position away from the path of said part will cause movement of said part, said means including a member constructed so that it is moved to one position when the hand of the operator is moved to place material. in position to be operated on, and so it is moved to another position when the hand of the operator is withdrawn.

10. The combination with a hand feed machine having a part movable in a definite path, for operating on material, of means connected with the hand of the operator whereby the movement of the hand of the operator to a position adjacent the path of Itlitl said part will prevent movement of said part, and whereby movement of the hand of the operator to a position away from the path of said part will cause movement of said part, said means including a member constructed so that it is moved to one position when the hand of the operator is moved to place material in position to be operated on, and so it is moved to another position when the hand of the operator is withdrawn.

11. The combination with a hand feed machine having a part movable in a definite path, for operating on material, of means connected with the hand of the operator and constrained in its movement with respect to the machine whereby the movement of the hand of the operator to a position adjacent the path of said part will prevent movement of said part, and whereby movement of the hand of the operator to a position away from the path of said part will cause movement of said part, said means including a member constructed so that it is moved .to one position when the hand of the operator is moved to place material in position to be operated on, and so it is moved to another position when the hand of the operator is withdrawn.

12. A press including a ram, means whereby movement of both hands of the operator to a position away from the path of the ram will cause movement of said ram, means for preventing said movement of both hands from causing more than one punching move-.

ment of the ram, and means whereby the movement of either hand of the operator to a position adjacent the path of the ram will cause the ram to be again controllable by said movement of both hands.

13. A press including a ram, means whereby movement of both hands of the operator to a position away from the path of the ram will cause movement of said ram, means for preventing said movement of both hands from causing more than one punching movement of the ram, means whereby the movement of either hand of the operator to a position adjacent the path of the ram will cause the ram to be again controllable by said movement of both hands, and means whereby the movement of a hand of the operator to a position adjacent the path of the ram will prevent movement of said ram.

14. A hand-feed machine for operating on material having a tool movable in a definite path, a movable member for controlling the operation of said tool, means for constraining the movement of said member with respect to said machine, and means whereby said member is constrained to move in unison with the hand of the operator in feeding material to the machine.

15. A hand-feed machine for operating on material having a tool movable in a definite path, a pair of movable members for controlling the operation of said tool, means for constraining the movement of said mem bers with respect to said machine, and means whereby one of said members is constrained to move in unison with one hand of the operator and the other member to move in unison with the other hand of the operator in feeding material'to the machine.

16. In a device of the character described, a hand-feed press for operating on material, a movable member for tripping its clutch, and means for controlling said movable member comprising a second movable member, means for constraining the movement of said second member with respect to said machine, and means whereby said second member is constrained to move in unison with the hand of the operator in feeding material *a definite path, automatic electrical means whereby the movement of the hand of the operator to a position adjacent the path of said part will automatically prevent movement of said part, and whereby movement of the hand of the operator to a position away from the path of said part will cause movement of said part.

18. A hand-feed machine for operating on material, having a tool movable in a defi-. nite path, and means for controlling the operation of said tool comprising a member constrained in its movement with respect to the machine and means for connecting said member to the hand of the operator.

19. A hand-feed machine for operating on material, having a tool movable in a definite path, and means for controlling the operation of said tool comprising a member pivotally mounted with respect to the machine and means for connecting said member to the hand of the operator.

20. A hand-feed machine for operating on material, having a tool movable in a definite path, and means for controlling the operation of said tool comprising a member movably mounted on said machine and means* for actuating said member comprising a member constrained in its movement with respect to the machine and means for connecting said member to the hand of the operator.

21. A hand-feed machine for operating on material, having a tool movable in a definite path, and means for controlling the operation of said tool comprising a rock-shaft mounted on the machine, an arm for rocking said shaft and means for connecting said arm to the hand of the o erator.

22. A hand-feed machine for operatin on material, having a tool movable in a efinite path, and means for controlling the op- In witness whereof, l have hereunto suberation of said tool comprising a rock-shaft scribed my name in the presence of two witmounted on the machine, means for rocking nesses.

said shaft comprising an arm mounted for REUBEN B. BENJAMIN. 5 swinging and sliding movement and means Witnesses:

for securing the swinging end of said arm W. PERRY HAHN,

to the hand of the operator. ANNE SOLOMON 

